Analysis Source of the Flash Fire A post-occurrence tank inspection revealed the presence of oil residue that was not present during a visual inspection the day before the occurrence. The residue's presence can be explained by the cycling of the stripping valve for COT No.5 starboard which is located in the adjoining tank (No.6 starboard) on the morning of the occurrence. This was demonstrated from April21 to April22 when the operating company performed a post-occurrence test by cycling the stripping valve for cargo tank No.5 starboard- at which point approximately 1.7cubic metres of water and cargo oil flowed back into the tank's suction well. The fire therefore likely occurred when combustible vapours from the back-flowing oil/water mixture that had entered that workspace were ignited by the welder's arc. Shipboard Safety Management The provision of adequate policies and procedures enables a ship's crew to be better equipped to make correct decisions of a day-to-day operational nature. By applying the ISM Code, shipping companies minimize the range of poor human performance-based decisions that may lead to an accident. An effective safety management system pursuant to the ISM Code requires that all risks be identified, with procedures put in place to minimize their potential impact. Part of the Kometik's shipboard safety manual (SSM) requires the identification of all procedures to be carried out ahead of any hot work in an enclosed space (such as a cargo tank). At the April8 safety meeting, however- where such risk assessment and permit issuing was to take place- no specific conflicting work items were identified, nor were any requirements identified for danger tag/lockout of pipes leading to the cargo tanks where hot work was to be performed. Several other SSM procedural requirements were also not followed: disposable coveralls were used, fire hoses were not charged, people in the tank did not carry an emergency breathing apparatus (EBA) or a portable gas monitor, and safety lines were not used. Although the SSM requires that such mitigating actions be identified in advance of any work, the procedures were not fully followed. Although the aforementioned tasks are all contained in the vessel's SSM, they were not carried out on the morning of the incident. This was due in part to the need to complete the tasks and get underway ahead of the advancing bad weather. Fatigue/Workload In the days leading up to the occurrence, the C/O was suffering from acute fatigue caused by several factors: He incurred a sleep debt by being awake for approximately 24 hours from April 3 to April 4 and then reportedly not getting restorative sleep for another two days; The unloading/cleaning work was demanding, both in terms of risk and time pressure; and He had been suffering from flu-like symptoms for several days. It is not known if the antidepressant being taken by the C/O contributed to his state of fatigue or if it in any way affected the performance of his duties. The C/O's greatest level of fatigue would have occurred two days before the accident when much of the repair work was being considered. It is likely that he was still in a fatigued state at the time of the accident, as he would have been unable to obtain sufficient restorative sleep to overcome the earlier sleep debt. According to the IMO's Fatigue and the Ship's Officer,14 fatigue can have a number of possible effects, including attitude change (such as failing to anticipate danger or ignoring normal checks and procedures) and diminished concentration and decision-making ability. The combination of excessive work hours and fatigue can result in negative effects such as increased risk-taking and increased use of shortcuts. Moreover, persons who are fatigued may not accurately assess their own level of fatigue. Since beginning that particular trip on April3, for example, the C/O was involved in extensive tank cleaning/cargo operations in addition to his duties directing and supervising the deck department's daily work, and monitoring repairs performed by shore contractors. Although a risk analysis and schedule was created for each of the individual activities, no risk analysis or workload analysis was carried out for the overall cleaning and repair activity. This lack of an overall plan and high workload while in a fatigued state likely had an impact on the C/O's performance. An effective safety management system pursuant to the ISM Code requires that all risks be identified, with procedures put in place to minimize their potential impact. In this instance, the vessel's SSM did not identify fatigue or workload as risk factors and did not incorporate procedures, such as an increased crewing level, which would mitigate those risks. It is therefore likely that, as a consequence of fatigue and workload, the C/Odid not recognize the potential conflict between the welding operation in cargo tank No.5 starboard and the valve repairs in the adjacent tank. As a result, he did not follow the existing SSM procedures to mitigate the risks. Personal Protective Equipment The disposable polyethylene coveralls worn by the welder did not meet the minimum requirements for performance of workwear for protection against hydrocarbon flash fires as contained in Canadian General Standards Board standard CAN/CGSB-155.20-2000, Workwear for Protection Against Hydrocarbon Flash Fire, nor did they meet the requirements of the Canada Labour Code to provide adequate personal protective equipment and clothing.15 These coveralls were not fire-resistant and they were contaminated with petroleum products from the tank's oily residue, which itself created a hazard. They therefore likely contributed to the severity of his injuries. Protective clothing available on the market includes items manufactured with fabric blends of 88percent cotton and 12percent high-tenacity nylon that is treated so as to extinguish combustion once the ignition source is removed. However, the coveralls supplied by the company as protective clothing for use on board the vessel were of 100percent cotton, and not suitable protection against high-temperature flash fires. Given the risk exposure of personnel working on oil tankers to flash fire incidents, the protective gear supplied or available to the crew members of the Kometik was not consistent with their risk exposure profile. Established procedures for hot work and enclosed spaces were not followed. A crew member with a high workload of safety-sensitive duties worked while in a fatigued state, leading to insufficient oversight of the welding activities. When conflicting work items were not identified during pre-planning, the cycling of the tank stripping valves on two occasions allowed a flammable air/hydrocarbon fuel mixture to form in the tank where hot work was to be performed. The atmosphere in cargo tank No.5 starboard was not tested immediately before or during the work, thereby allowing an explosive atmosphere to go undetected. The welder's arc introduced an ignition source for the flammable atmosphere in the tank. Neither the welder nor the crew member carried appropriate personal protection equipment while working in the tank, thus exposing them to the risks associated with their assigned work. The disposable polyethylene coveralls worn by the welder likely contributed to the severity of his injuries.Findings as to Causes and Contributing Factors Established procedures for hot work and enclosed spaces were not followed. A crew member with a high workload of safety-sensitive duties worked while in a fatigued state, leading to insufficient oversight of the welding activities. When conflicting work items were not identified during pre-planning, the cycling of the tank stripping valves on two occasions allowed a flammable air/hydrocarbon fuel mixture to form in the tank where hot work was to be performed. The atmosphere in cargo tank No.5 starboard was not tested immediately before or during the work, thereby allowing an explosive atmosphere to go undetected. The welder's arc introduced an ignition source for the flammable atmosphere in the tank. Neither the welder nor the crew member carried appropriate personal protection equipment while working in the tank, thus exposing them to the risks associated with their assigned work. The disposable polyethylene coveralls worn by the welder likely contributed to the severity of his injuries. Given the risk exposure of personnel working on oil tankers to flash-fire incidents, the protective gear supplied or available to the crew members of the Kometik was not consistent with their risk exposure profile. The vessel's shipboard safety manual did not identify fatigue or workload as risk factors and did not incorporate procedures to mitigate them.Findings as to Risk Given the risk exposure of personnel working on oil tankers to flash-fire incidents, the protective gear supplied or available to the crew members of the Kometik was not consistent with their risk exposure profile. The vessel's shipboard safety manual did not identify fatigue or workload as risk factors and did not incorporate procedures to mitigate them. Safety Action Action Taken Operating Company Following this occurrence, the tanker ships Kometik, Vinland, and Mattea were provided with an additional officer to ease the workload on the chief officer of each vessel. In addition, all work planning is now monitored monthly by shore personnel. The company's quality and safety management system (QSMS) has been revised and updated. The pre-critical task meetings as well as the job site planning meetings (Toolbox meetings) were reviewed and improved. Seminars were conducted for shore staff with ships' crews in attendance focusing on responsibility and accountability regarding safety on ships. The revised QSMS reinforces the employer requirement that the master be informed of any prescription medication that crew members may be taking. Recent changes in the seafarer's medical examinations (under the Canada Shipping Act, 2001) add to this employer requirement.